1. Field of the Invention
The present invention relates to digital televisions, and more particularly to a method for switching between minor channels for digital televisions which can change a minor channel when the minor channel enters a non-signal state or become a hidden channel.
2. Description of the Related Art
Generally, television broadcasting permits the user to watch a broadcast of a desired channel by determining whether respective broadcast signals, as received through all receivable channels allocated to broadcasting stations, are analog signals or digital signals, followed by selection of an analogue or digital mode based on a determination result in channel navigation.
With an increasing interest in digitalization by the recent development of communication techniques, a digital broadcast service has been provided to select and display a television broadcast or a channel having a digital signal.
In such a digital broadcast service, information as to a channel selected from a previously stored channel map is searched for when the user selects the channel on a remote controller.
Based on the search result, a frequency band of the selected channel is selected and a digital signal carried by the frequency band is then subjected to demodulating, de-multiplexing, and decoding operations to output video and audio.
In such digital broadcasting, a compression method capable of providing high channel efficiency is employed to transmit a number of programs through each channel, wherein a physical channel is referred to as a major channel and a virtual channel for transmitting the respective programs is referred to as a minor channel.
Since allocation of minor channels is determined by broadcasting stations, channel number of the minor channels can be changed, and the minor channels can also be subjected to change from a signal state to a non-signal state.
Further, the minor channels can be provided as a channel for supplying only an audio signal, a channel for supplying only a video signal, or a hidden channel which cannot be watched by the user.
When a certain minor channel enters the non-signal state, a letter conventionally indicates the non-signal state of the minor channel, and in this case, the non-signal state of the minor channel is disadvantageously maintained until the user switches from the minor channel in the non-signal state to another channel.
Further, when a certain minor channel becomes a hidden channel while the user watches this minor channel, the television switches from the minor channel to a major channel and the user cannot watch this minor channel any more, causing an inconvenience of converting again the major channel into the minor channel. Therefore, there is a need for a technique which can overcome such problems of the conventional techniques.